EWI-747 Lime Render NHL 3.5 is the flagship product in the EWI Pro Heritage Range, designed for projects where breathability, durability and long-term building health are essential. Formulated using natural hydraulic lime, it allows moisture to move freely through the building fabric, helping walls dry naturally rather than trapping damp.

Unlike cement-based renders, EWI-747 sets through carbonation, meaning it gradually absorbs CO₂ as it cures. With NO chemical additives, it offers a completely natural, sustainable and aesthetically timeless finish, making it particularly well suited to heritage renovations and traditional masonry buildings.

Intended Uses

EWI-747 Lime Render NHL 3.5 is suitable for both internal and external applications, making it a highly versatile solution for a wide range of projects, including:

• External walls on solid brick, stone and traditional masonry
• Chimneys and exposed heritage features
• Internal walls where breathability is required
• Renovation and conservation projects
• Situations where traditional, vapour-permeable materials are specified

It is especially appropriate for older buildings where moisture needs to be managed naturally rather than sealed in.

Key Benefits

• Highly breathable, allowing moisture vapour to pass through walls
• Stronger and more robust than softer lime renders, while remaining flexible
• Far more breathable and forgiving than cement-based alternatives
• Helps reduce damp issues and prolong the life of the structure
• Accommodates subtle building movement, minimising cracking
• Smooth, workable consistency for an authentic traditional finish
• Completely natural and eco-friendly, with no chemical additives
• Absorbs CO₂ during carbonation, supporting sustainable construction

Compatible Products

EWI-747 Lime Render NHL 3.5 is compatible with a range of breathable lime-based finishes, allowing the system to be tailored to the required appearance while maintaining vapour permeability.

EWI-747F Fine Finish Lime Render NHL 3.5

EWI-747F is specifically designed to be applied over EWI-747 where a finer, smoother traditional finish is required, while maintaining the same breathability and flexibility.

EWI-749 Fine Finish Lime Plaster

Where a more refined decorative finish is required, EWI-749 can be applied over EWI-747 provided the render is flat, sound and properly cured, creating a smooth lime finish while maintaining breathability.

EWI-707 Lime Wash

Lime Wash is a breathable finishing and sealing coat for EWI-747, helping to protect and unify the surface during carbonation while allowing moisture to evaporate naturally.

EWI-705 Lime Paint

Once EWI-747 has fully cured, Lime Paint can be applied as a decorative finish where colour consistency or enhanced durability is required, without restricting vapour permeability.

Lime Wash and Lime Paint can also be blended together to create bespoke, heritage-style finishes where appropriate.

EWI-747 should only be used and finished within breathable lime-based systems to ensure long-term performance and moisture management.

Substrate Preparation

Substrates must be firm, clean and free from contaminants that could impair adhesion, including dust, grease, oils, efflorescence, salts, biological growth or loose material.

Prior to application, the substrate should be pre-dampened with clean water, ensuring it is moist but not saturated. This is critical to prevent rapid dehydration, which can lead to cracking and poor curing.

On older or uneven backgrounds, it is recommended to level the surface using the same mortar and allow it to harden before applying the final render layer, ensuring consistent thickness and finish.

Product Preparation

Mix EWI-747 Lime Render exclusively with clean water at a rate of 4-5 litres per 23 kg bag.

• Add water to a clean container first
• Gradually introduce the powder while mixing
• Mix for 3–5 minutes until a smooth, lump-free consistency is achieved

Avoid adding excess water, as this can reduce mechanical strength and increase the risk of cracking. Once mixed, the mortar has a working time of approximately 60 minutes. For larger volumes, use a forced-action or concrete mixer.

Application

EWI-747 Lime Render can be applied by hand using a trowel or using a spray machine.

• Typical application thickness: 4-10 mm
• For thicknesses greater than 10 mm, apply in multiple coats, allowing each layer to firm up before applying the next
• Once applied, float the surface to achieve the desired finish

Clean all tools and equipment with water immediately after use. Do not allow waste material to enter drainage systems.

Learn how to install EWI-747 Lime Render NHL 3.5

Technical Data

Storage Conditions

Store in original, unopened packaging in a cool, dry location, protected from moisture and frost. Avoid water ingress at all times. Shelf life is up to 12 months from the date of manufacture when stored correctly.